Late Partial Dissociation of a Humeral Head Morse Taper Associated with Periprosthetic Proximal Humeral Fracture: A Case Report.

CASE: A fifty-two-year-old man who had undergone total shoulder arthroplasty ten years previously presented following a mechanical fall onto his operatively treated shoulder, resulting in a periprosthetic humeral fracture and partial dissociation of the humeral head from the stem. CONCLUSION: Shoulder surgeons should consider late disengagement of the Morse taper as a potential cause of surgical failure. Partial late dissociation of the humeral head from the stem after shoulder arthroplasty is possible and can be associated with a fracture. The shoulder surgeon should be aware of this potential complication when evaluating periprosthetic proximal humeral fractures, emphasizing the importance of attention to detail when evaluating patients.

Clinical application of C2 laminar screw technique.

C2 laminar screws have become an increasingly used alternative method to C2 pedicle screw fixation. However, the outcome of this technique has not been thoroughly investigated. A total of 35 cases with upper cervical spinal instability undergoing C2 laminar screw fixation were reviewed. All cases had symptoms of atlantoaxial instability, such as craniocervical junction pain, and were fixed with the Vertex cervical internal fixation system. A total of 68 screws were placed and hybrid constructs (a C2 translaminar screw combined with a C2 pars screw) were incorporated in two patients. In this series, there were no intraoperative complications and no cases of neurological worsening or vascular injury from hardware placement. Computed tomographic scans demonstrated a partial dorsal laminar breach in ten patients. None of these resulted in neurological symptoms. None of the patients was found to have a breach of the ventral laminar cortex. All the C2 laminar screws fixations were performed successfully. There was no instability seen on the films with no evidence of hardware failure or screw loosening during the follow-up period in all patients. In conclusion, C2 laminar screw technique is straightforward and easily adopted; it can efficiently and reliably restore upper cervical stability. It is an alternative method to C2 pedicle screw fixation, especially in patients with unilateral occlusion of vertebral artery and pedicle deformity of C2.

Balloon kyphoplasty in the treatment of osteoporotic vertebral compression fracture nonunion.

Patients with nonunion of osteoporotic vertebral compression fractures that are refractory to conservative treatments have persistent back pain, progressive vertebral body collapse and kyphosis, and mobility of the fracture. Although many previous reports have reported vertebral compression fractures treated by balloon kyphoplasty, few data is available on using this method to treat nonunion of vertebral compression fractures. This study evaluated the therapeutic potential of balloon kyphoplasty in the treatment of nonunion of osteoporotic vertebral compression fractures. Twenty-one patients with nonunion of osteoporotic vertebral compression fractures were treated with balloon kyphoplasty. The criteria for diagnosis of nonunion osteoporotic vertebral compression fractures included the following: (1) history of pain for at least 6 months at the fracture site; (2) low T1- and high T2-signal on magnetic resonance images; (3) widening of fracture line on routine radiographs; and (4) movement of the endplate and changes of anterior vertebral heights on hyperextension radiographs. All patients were followed for 9 to 33 months postoperatively (mean 25 months). Statistically significant improvements in the mean postoperative anterior and middle vertebral body heights were observed compared with preoperative values. There was also statistically significant improvement in the mean values for Cobb's angle, pain (visual analog scale), and the Oswestry Disability Index at the postoperative assessment compared with the preoperative assessment. No statistically significant differences were noted between the postoperative and final follow-up assessment in any of the evaluated efficacy measures. The study suggests that balloon kyphoplasty is an effective technique to treat nonunion of osteoporotic vertebral compression fractures.

Comparison of angled versus AP view radiography for post-operative evaluation of lumbosacral spondylolisthesis: a cadaveric study.

BACKGROUND: The objective of this study was to investigate if angled radiographic views of the L5-S1 junction result in quantitatively better images in patients with lumbosacral spondylolisthesis compared to conventional AP view. METHODS: Grade I lumbosacral spondylolisthesis was simulated in cadaveric specimens and repaired using pedicle screws and posterolateral bone grafting. Angled view AP radiographs were taken at different angles and analyzed at both grade I spondylolisthesis and complete reduction (to normal). RESULTS: The results indicated that angled view radiographs provide better visualization of intervertebral disc height, area, and posterolateral bone graft area compared with true AP views. The optimal view was at 40 degrees for grade I spondylolisthesis, and at 25 degrees -35 degrees for complete reduction. CONCLUSION: In addition to the dynamic radiographs currently used for evaluation of patients post-spondylolisthesis repair, an additional angled view radiograph (at 40 degrees or 25-35 degrees ) is recommended to evaluate intervertebral disc height, intervertebral area, bone graft area, and pedicle screw position.